The companies were indicted in August on charges of fixing the bids to divide up the contracts to build 12 LNG tanks in three provinces from 2005 to 2012. It marked the biggest-ever rigging in terms of the value of the contracts involved.

Six other builders were fined between 20 million won and 140 million won.

Company officials accused of involvement in the rigging were also sentenced to fines ranging from 5 million won to 30 million won.

"The defendants colluded and impeded competition in order to maximize profits," the court said in the verdict. "This kind of act greatly damages the legislative intent of the Monopoly Regulations Act ... This should be sternly punished, as the damage from the rigging was handed over to the people while the profits the defendants gained are not small."

The court said, however, that it took into consideration the fact that massive penalties have already been imposed on the companies. The antitrust watchdog Fair Trade Commission has slapped the builders with a total of 351.6 billion won in penalties, the second-largest amount for such irregularities involving builders. (Yonhap)